Cheap SCSI setup?

Energize · 27 Oct 2007 at 05:04

What sort of performance could I expect if I bought a cheapo Ultra 160 scsi card and some cheapo 18GB 10k drives? Thought it might be interesting to try it out. Latency would matter to me more than throughput, as thats what affects load times. I've heard that just the fact that your using a controller for hard drives means there isn't any hdd lag when burning dvds or other activies like that. So far I've found.

FUJITSU SIEMENS U160 SCSI PCI CONTROLLER S26361-F2644-L3 £16

4x Compaq Proliant 18.2GB 10K Ultra 3 SCSI £35

rpstewart · 27 Oct 2007 at 10:53

SCSI can be an interesting learning experience and for those kind of prices (I assume that's £35 for the four drives not each) it's probably worth a punt. Don't expect stellar performance though, the access times on those disks will be good (think Raptor speeds) but the transfer rates won't be spectacular since we're talking about 3-4 year old technology. You're also pairing them up with a PCI controller so there will be a bandwith limitiation there although the card doesn't support RAID so you'll be hard pushed to shift any more data than the PCI bus can handle.

Energize · 27 Oct 2007 at 17:54

Doesn't pci 2.2 support 533MB/s ? Can raid be done in the os?

rpstewart · 27 Oct 2007 at 18:46

Energize said:
Doesn't pci 2.2 support 533MB/s ?

Yes, but only over 64bit / 66MHz slots which only tend to be found on server boards.

Energize said:
Can raid be done in the os?

Yes, but there are limitations. 1) You need an OS which supports Dynamic Disks (most versions of Vista don't) & 2) I'm not sure that you can boot from a striped dynamic disk.

Energize · 27 Oct 2007 at 19:15

rpstewart said:
Yes, but only over 64bit / 66MHz slots which only tend to be found on server boards.

Is it possible to use two controller cards to achieve double the bandwidth?

Combat squirrel · 27 Oct 2007 at 20:54

try for 2 15k drives then you will see an improvement

rpstewart · 27 Oct 2007 at 20:58

Energize said:
Is it possible to use two controller cards to achieve double the bandwidth?

Not on PCI, the bandwidth is shared across the whole bus. Although some server boards do have multiple PCI busses for exactly this purpose.

Energize · 27 Oct 2007 at 21:30

Ugh PCI seems so badly designed.

rpstewart · 27 Oct 2007 at 21:50

It only seems poor in today's context - it's a 15 year old standard remember. The leap from 16bit 8MHz ISA slots to 32bit 33MHZ PCI ones in the mid 90s was just as big as the jump to PCIe is today.

The problem with PCI has been it's too good, for just about any everyday task it's more than adequate and because it can't deal with (in relative terms) huge bandwidths it's easy to lay out on circuit boards. It's cheap and cheerful and does the job, unfortunately it's starting to show it's age.

Energize · 27 Oct 2007 at 23:29

Is there any other way to get better bandwidth on a normal board? Like a pci-e card or pci-e to pci-x adaptor?

rpstewart · 28 Oct 2007 at 08:43

If you've got free PCIe slots then that's the way to go, even a 1x slot has 250MB/s of dedicated bandwidth, almost twice that of an entire 32bit PCI bus. Finding a card might be a bit tricky, there are a few 8x Dell PERC RAID cards up for auction but they tend to go for a couple of hundred each. Adaptec do a 1x plain SCSI card but you're still looing at £100 new.

Energize · 28 Oct 2007 at 22:28

Would it be possible to use 2 pci controllers, one on the pci bus, and one on the pci-e bus using an adaptor?

rpstewart · 28 Oct 2007 at 22:33

I'm not aware of any form of adapter which will allow a PCI card to operate in a PCIe slot, the signalling of the two interfaces are too different for it to work - one is 5V & parallel, the other is 3.3V and serial.

Energize · 28 Oct 2007 at 22:35

This is what I found on google.

http://www.virtuavia.eu/shop/index.php?target=products&product_id=29855&sl=EN

rpstewart · 29 Oct 2007 at 08:23

Interesting.... Might be a struggle to get a full height card into some cases but that's a minor issue. Obviously you'll still be limited to the 133Mb/s PCI bandwidth but it'll be dedicated to that one card rather than shared.

Avalon · 29 Oct 2007 at 11:38

It all depends on the drives TBH. Storage Review will give you a good indication of what they are like compared to more recent hardware. For what it's worth I picked up a cheap adaptec 320 raid card and a pair of 68pin 300GB 10k Fujitsu MAW's with plans to run RAID0 on then not so long back. Simply put they fly. I also have a smaller raid 5 array on another box but it was more about education than speed as despite being 10k they are slow performance wise, it was more to test the rebuild process. For simplicity you could consider a pair of 2nd hand 36GB Raptors in RAID 0, they wouldn't run to much more than you're paying for the kit you outline. Also have you checked those 4 drives aren't SCA ? Just if they are you will need an adapter for each drive if they don't come with them....

cavemanoc · 29 Oct 2007 at 22:32

I'm running a selection of 15k cheetahs off a Dell Perc 4e d/c and it is, as described by RPStewart, an interesting learning experience. I'm maxed out at 160mb/s ish as are most of us running this combo, so your selection of u160 isn't the end of the world, but you really do need to look at a Pci-e solution if you want anything more than a bit of fun.

The low access time is great, and I do get into BF2 1st (every time

) but TBH the difference these days is tiny (couple of seconds) as there is a lot more to level loading times than pure drive speed/access time (unfortunately). We had a great debate about this a little while back - will try to dig out the thread - and the bottom line was that even running off a RAMDrive, you gained only a small advantage, so it really isn't worth the effort (or money).

You're better off getting a couple of the new Samsung F1s and raiding them next month if you want fast transfer speeds. (Especially on the new intel matrix controllers which seem awesome!)

That said - Scsi is great fun, and pretty cool - especially the new Sas stuff, but it is hugely expensive at the bleeding edge. If you can track down a cheap controller card (pci-e) the Seagate Cheetahs (15k3) 18Gb drives can be had cheaply and are pretty quick. Do watch out for the model numbers as the 80 pin ones are a nuisance - the adapters are only a couple of quid, but they're not as reliable as the 68 pin ones if you don't invest in a proper backplane.